Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information EFI-443

EFI-443 Three-way catalytic converter (TWC) efficiency

Condition




The engine control module (ECM) continuously monitors three-way catalytic converter (TWC) efficiency by comparing the signal from the rear heated oxygen sensor (HO2S) with the signal from the front heated oxygen sensor (HO2S). When three-way catalytic converter (TWC) efficiency deviates too much the engine control module (ECM) stores diagnostic trouble code (DTC) EFI-443.

Substitute value
- none.

Possible source
- uneven compression
- air leakage in the intake system
- air leakage in the exhaust system
- faulty fuel pressure
- defective three-way catalytic converter (TWC).

Fault symptom[s]
- may result in poor performance.